Vendors often invoice in stages — one invoice per delivery, or one now and one when the rest ships. You can record each as its own bill against the same purchase order.
Add a second bill
Open the purchase order and click the Bills tab.
Click New bill.
Enter the second invoice number and its dates.
Set the quantities to what this invoice covers — not the whole order.
Click Create.
The Qty Not Billed column shows what is still outstanding, so you can see what this bill should cover.
What Brahmin Solutions checks
The total across all bills cannot exceed what was ordered. If you try, it refuses and tells you how much is left to bill.
Bills do not have to arrive in any particular order, and they do not have to line up with your deliveries. Three deliveries and two invoices is perfectly normal.
What changes once there are two
Once an order has two or more bills, you cannot reduce quantities on the order. You will see: "Cannot reduce quantity as multiple bills exist. Please adjust bill quantities first."
Fix the bills first, then the order.
Changing a price on the order rewrites every bill against it. With several bills that means all of them, including ones you have already entered from paper invoices. Check with whoever handles your accounts before changing a price on a multi-bill order.
How to know it worked
Both bills appear on the Bills tab, and the Billing progress bar reflects the combined total. When everything is billed it reads 100%.